Asking someone to be quiet or to shut up.让某人安静或者别出声
The origins for this expression are unclear. 这个词组的来源不是很清楚。It's not really known why a sock is being used, or what the 'it' in the phrase refers to. 至于这里为什么用袜子以及it指代的是什么，这些也不是很清楚。 It might be a person's mouth, or it could be something else. It有可能指代的是一个人的嘴或者其他东西。
This phrase is occasionally directed at people who are being annoyingly loud. 这个词组被用来描述一个很吵闹的人。The imagery for this idiom is that someone is being so noisy, a sock is stuff into their mouths in order to quiet them down. 大意就是这个人很闹，所以他的嘴里被塞袜子，这样就安静下来了。
1.Put a sock in it! I'm tired of your silly jokes.
2. Can't you put a sock in it when I am on the phone?